6565 has 8 divisors (see below), whose sum is σ = 8568. Its totient is φ = 4800.

The previous prime is 6563. The next prime is 6569. The reversal of 6565 is 5656.

6565 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 4 ways, for example, as 1089 + 5476 = 33^2 + 74^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6565 - 2¹ = 6563 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

6565 is an undulating number in base 10.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15 + ... + 115.

It is an arithmetic number, because the mean of its divisors is an integer number (1071).

2⁶⁵⁶⁵ is an apocalyptic number.

6565 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

6565 is a deficient number, since it is larger than the sum of its proper divisors (2003).

6565 is a wasteful number, since it uses less digits than its factorization.

6565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119.

The product of its digits is 900, while the sum is 22.

The square root of 6565 is about 81.0246875958. The cubic root of 6565 is about 18.7245580860.

Subtracting from 6565 its product of digits (900), we obtain a palindrome (5665).

Adding to 6565 its reverse (5656), we get a palindrome (12221).

Subtracting from 6565 its reverse (5656), we obtain a palindrome (909).

The spelling of 6565 in words is "six thousand, five hundred sixty-five".